With Git you will make a copy
of the entire code repository on your local machine, so you will
have access to all history and branches offline. This is the
fastest and most flexible way to develop or test patches.

Git

You will need an installed version of Git, which you can get from http://git-scm.com.
Many systems already have a recent version of Git installed by default, or available
in their package distribution system.

To begin using the Git repository, make a clone of the
official mirror:

git clone git://git.postgresql.org/git/postgresql.git

This will copy the full repository to your local
machine, so it may take a while to complete, especially if
you have a slow Internet connection. The files will be
placed in a new subdirectory postgresql of your current directory.

The Git mirror can also be reached via the HTTP
protocol, if for example a firewall is blocking access to
the Git protocol. Just change the URL prefix to http, as in:

git clone http://git.postgresql.org/git/postgresql.git

The HTTP protocol is less efficient than the Git
protocol, so it will be slower to use.

Whenever you want to get the latest updates in the
system, cd into the repository,
and run:

git fetch

Git can do a lot more things
than just fetch the source. For more information, consult the
Git man pages, or see the
website at http://git-scm.com.